Dual nano encapsulation of multi-strain probiotic bacteria can enhance their viability within the avian gastrointestinal tract and improve their effectiveness in disease prevention. So that this study spotted the light on the effect of dual nano encapsulated multi strain of probiotics (LEBB-NPs) contained Enterococcus faecium NCTC 7171, Bacillus amyloliquefaciens probiotic CECT 5940, Lacticasei bacillus casei ATTC334 and Bifidobacterium breve JCM1192 on laying performance, egg quality, immune defence, and resistance against Salmonella Typhimurium challenge. A total of 250 Ross 308 laying breeder hens, 20 weeks of age, were randomly allocated into five experimental groups (five replicates per group; 10 hens per replicate). The control group received a basal diet only and was not challenged. Infected control: hens received basal diet only and challenged with S. Typhimurium (1 × 106 CFU/hen) at week 34 of age. Groups LEBB-NPsI, LEBB-NPsII and LEBB-NPsIII fed basal diet supplemented with dual nano encapsulated multi strain of probiotics at levels of 1 × 106 CFU/kg diet, 1 × 108 CFU/kg diet and 1 × 1010 CFU/kg diet respectively and challenged with Salmonella Typhimurium (1 × 106 CFU/hen) at weeks 34 of age. The results indicated that